Thomas Shigeru Miyashiro was born in Waimanalo, Hawaii, on April 25, 1915. Both of his parents had immigrated from Okinawa. Like many nisei, he was known as "Shigeru" to his Okinawan friends and "Thomas" to others. Miyashiro practiced martial arts from a very young age and was fortunate to have had the opportunity to train under visiting Karate instructors Kentsu Yabu, Choki Motobu, Mizuho Mutsu, Kamesuke Higashionna, and Chojun Miyagi, as well as other Karate instructors who resided in Hawaii such as Seishin Uehara. In 1933, Miyashiro was one of the founding instructors of the Hawaii Karate Seinenkai.

Miyashiro lived in the Ft. Street area of Honolulu growing up. In later life, he lived at the Wahiawa Botanical Gardens. Four of his students there were Takamasa Bingo, Robert Kato, Raymond Higa, and Eddie Ueshiro.

From his early twenties, Miyashiro suffered from a chronic heart condition. Many people would have given up Karate training, but he never did. He devoted his life to preserving and speading the art of Karate. Through the dedication of this family, Miyashiro's remarkable role in the early history of Karate has been preserved. Prior to the reestablishment of the Hawaii Karate Seinenkai, Mrs. Miyashiro's permission was requested and generously given. The Seinenkai wishes to thank the Miyashiro family for its support and salutes the life and accomplishments of a truly great man, Thomas Shigeru Miyashiro.